Type 1 leprosy reaction in a patient coinfected with HTLV-1 and Mycobacterium leprae

Coinfection with HTLV-1 and Mycobacterium leprae can present significant clinical challenges due to their complex interactions. The chronic immune activation induced by HTLV-1 can potentiate leprosy-related neurological symptoms, complicating treatment. This report describes a 61-year-old man from a Brazilian endemic area for HTLV-1 and leprosy, who was diagnosed with both infections and developed a type 1 leprosy reaction. The patient presents a significant exacerbation of neurological symptoms, with sensory and motor impairments across multiple limbs. Routine screening for HTLV-1 in patients diagnosed with leprosy, especially in endemic areas, is essential for better clinical management and prognosis.